Steam-boiler



(No Model.)

N. W. PRATT.

STEAM BOILER.

No. 275,787. Patented Apr. 10,1883.

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NITED STATES PATENT 3 STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 275,787, dated April 10, 1883.

Application filed November "22, 1882, (No model.)

To all whom it may concern Be it known that I, NATHANIEL W. PRATT, of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements relating to Steam-Boilers, of which the following is a specification.

My invention applies to all that class of boilers in which water is circulated in many small pipes through the furnace or through the hot gases rising therefrom.

I have devised an improved construction of the headers, by which term I designate the parts by which the ends of the tubes are connected to each other and to the barrel or other chamber above. I make the headers sectioned in both directions,vertical and horizontal, and also provide in combination therewith a separate hand-hold cover and means for fastening it, arranged in line with each tube. This allows for the expanding of the tubes at their junctions with the headers and for the subsequent tightening of a leaky junction, as also for the removal and substitution of a tube, when necessary, without disturbing any part, except that immediately connected in front of the defective tube. This allows of peculiar provisions for removing ashes from the spaces between the three tubes.

The following is a description of what I consider the best means of carrying out the invention as applied to the style of boiler known as the Babcock & Wilcox.

The accompanying drawings form a part of this specification.

Figure l is a side elevation of the boiler in the position for use, but without the masonry or other accessories. The succeeding figures show those details to which the invention more particularly relates on a'larger scale. Fig. 2 is a front view of a portion of the headers. Fig. 3 is a vertical section on the lines s in Fig. 2. Fig. 4. shows a modification.

Similarletters of reference indicate like parts in all the figures.

A is the ordinary barrel of-the boiler.

B B, &c., are ordinary'inclined tubes bathed in flames from the furnace, through which tubes 7 the water in the boiler circulates.-

O C are the ordinary connections between the barrel and the headers. The headers are formed in small sections connected together in vertical series, each series independent of its neighbor. Each vertical series is formed of a number of separate boxes or chambers, D D &c., connected together, one above the other, by thimbles H of as large diameter as the construction will conveniently allow. Each chamber D or D receives three of the tubes B. It may be tightly connected thereto by the expansion of the tube in a close-fitting hole in the well-known manner. A hand-hole, b,is provided opposite to each tube end ofjust sufficient size to allow the introduction or removal of a tube. A hand-hole cover, E, is provided for each, with a suitable cross-bar, F, bolt G, and cap-nut G. The contact-surfaces of the covers E and their seats around each handhole I) should be accurately finished, so as to make steam-tight contact. Packing may be employed, ifdesired. Each box or chamber, as D, is equipped to receive three tubes, B, and there are three of the hand-holes b, with their covers E and fastening means F G G, ar-

ranged in a triangular form. The forms of the chambers allow the several compound headers thus formed to applyclosely together byinverting each alternate compound header. When so arranged they hold the tubes staggered, or properly'out of right lines, one above the other. A central stay, cl, strongly connects the front with the back of each chamber. It may be cast in one therewith. It is hollow, and, in addition to its strengthening and stiffenin g the chamber, serves the additional function of affording facilities for the application of a nozzle and injecting a strong blast of steam at intervals to remove ashes or other foreign matter which may be lodged between its connected tubes'B.

The sides of the several chambers may be recessed at certain points, as indicated at t, Fig. 4, so arranged that when the several series of headers are applied together the recesses form apertures through which blasts of steam may also be introduced.

The thimbles or short tubes H may be of good iron, capable of being expanded. In applying the parts together the thimble is first set in one of the chambers, as D, and then the next chamber, as D is applied in the proper position, receiving the unexpanded end of the thimble, and a suitable expanding-tool being introduced and operated, that end is expanded, and the junction of the two chambers by the now fully expanded thimble H is complete.

I use for the second expansion a form of expanding-tool which can be operated through the hand-hole.

The hand-holes, with their independent covers E and securing means, allow access to each tube for setting, tightening, or otherwise treatin g it, or for removiu g it, without the necessity for otherwise opening the front of the chamber or in any wise disturbing the workin front of any other tube. This allows the tubular stay (1 to form a permanent part of the structure. It is preferably cast as a part of the chamber, all in one piece. Making such stay hollow affords facilities for clearing by a blast of wind or steam a space between the three tubes which would not be otherwise accessible. The apertures 'i, allowed in the angular junctions of the chambers and the recesses i in Fig. 4, are available to allow other spaces to he also cleared.

Modifications may be made in the forms of the parts without departing from the principle or sacrificing the advantages of the invention. I can realize some of the advantages without the recesses 'i and without the hollow interior in the stay d.

I can apply the invention to other forms of boiler than the Babcock & Wilcox. It may be used successfully in most forms where there are thickly-set tubes to be connected to headers.

I claim as my invention- 1. The triangular chambers D D, arranged in series, alternately reversed, as shown, adapted each to receive three tubesand hold them equidistant, in combination with such tubes and with connecting-thimbles H, and with suitable connections with a steam separating chamber, as A, arranged at a higher level, as specified.

- 2. The triangular chambers D 1), arranged reversely, as shown, and provided with each a central thimble or support, d, adapted to allow strong jets of steam or air to be iniected through the spaces 1' at the junctions of the chambers, and alsothrough the said thimbles d, to remove dust or soot from the pipes, substantially as set forth.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

NAT. W. PRATT.

Witnesses:

E. S. IRMET, A. H. GENTNER. 

